An image forming apparatus of an electrophotographic system such as a printer or a MFP (Multi Function Peripheral), which uses a toner as a color material, heats and melts an unfixed toner image carried on a printing sheet and fixes the toner image on the printing sheet in a fixing device.
In the image forming apparatus of the electrophotographic system, to receive a request for printing and start the printing, it is necessary to heat the fixing device to a ready temperature, which is a printable temperature at normal speed. When the fixing device is heated, for example, if printing is not performed for a long time, since the heating device is cooled, it takes a long time to warm up the fixing device to the ready temperature for enabling fixing. Therefore, in some case, for example, even if only a few sheets are printed, the fixing device is not ready for sudden printing.